Germanium smoothing and chemical mechanical planarization processes

ABSTRACT

Method for chemical mechanical planarization is provided, which includes: forming a dielectric layer containing at least one opening, the dielectric layer is located on a substrate; epitaxially growing a germanium material within the at least one opening of the dielectric layer, the germanium material extending above a topmost surface of the dielectric layer; and planarizing the germanium material using at least one slurry composition to form coplanar surfaces of the germanium material and the dielectric layer, where a slurry composition of at least one slurry composition polishes the germanium material selective to the topmost surface of the dielectric layer, and includes an abrasive, at least one pH modulator, and an oxidizer, the at least one pH modulator including an acidic pH modulator, and lacking a basic pH modulator.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional PatentApplication No. 62/241,459 filed Oct. 14, 2015, the entire content anddisclosure of which is incorporated herein by reference.

BACKGROUND

The present application relates to a semiconductor structure and amethod for fabricating the same. More particularly, the presentapplication relates to slurry compositions and methods for planarizing agermanium material for use, for instance, with fabrication ofsemiconductor structures, such as, p-type MOSFETs (PFET) devices.

As the density of semiconductor integrated circuits increases and thecorresponding size of circuit elements decreases, one of the keystrategies to increase performance at lower operating voltages is toincrease carrier mobility in the channel region. By way of an example,the carrier mobility in the channel region may be enhanced, forinstance, by employing non-silicon, high mobility charge carriermaterials, such as, for example, germanium or a III-V compoundsemiconductor materials, in the fabrication of the channel region. Forinstance, germanium, a group IV semiconductor material which, forinstance, has a highest hole mobility is utilized for fabrication ofPFET devices.

The fabrication of germanium on a semiconductor substrate, such as, asilicon wafer, disadvantageously, leads to several issues such as, forinstance, defect densities, owing to lattice mismatch of germanium andthe silicon wafer. Aspect ratio trapping is one way to overcome thelattice mismatch which, for instance, includes trapping threadingdislocations of the germanium material along the sidewalls of adielectric layer disposed over the semiconductor substrate, such as, forinstance, a silicon substrate. This results in a germanium material thathas a lower region containing a first defect density and an upper regionof a second defect density that is less than first defect densitypresent in an aspect ratio trench. This upper region of the germaniummaterial extends above the dielectric layer, and is subsequentlyplanarized using one or more chemical mechanical planarization (CMP)processes. Prior art CMP processes tend to cause unwanted damage to theupper region of the germanium material.

Enhancements in CMP processing techniques and slurry compositionsemployed in such technology is continue to be desired for enhancedperformance, while minimizing surface and sub-surface damage of theupper region of the germanium material.

SUMMARY

A method is disclosed in which a germanium material extending above atopmost surface of a dielectric layer present on a substrate isplanarized to form coplanar surfaces of a remaining portion of thegermanium material and the dielectric layer. The method includesepitaxial growth of a germanium material within one or more openings,i.e., trenches, of the dielectric layer. The epitaxially grown germaniummaterial has a lower region having a first defect density, and an upperregion having a second defect density that is less than the first defectdensity that is present in each opening. The upper region of thegermanium material extends above the topmost surface of the dielectriclayer. The upper region of the germanium material that extends above theopenings is planarized using at least one slurry composition. In thepresent application, each slurry composition of the at least one slurrycomposition has a different removal rate selectivity towards thegermanium material and the dielectric layer. In one embodiment, a slurrycomposition of the at least one slurry composition may include anabrasive, at least one pH modulator, and an oxidizer. In the slurrycomposition, the at least one pH modulator may include an acidic pHmodulator, and it may lack a basic pH modulator. In such an example, theslurry composition has a rate of removal of the dielectric layer that isless than a rate of removal of the germanium material, and thus polishesthe germanium material selective to the upper surface of the dielectriclayer, thereby forming coplanar surfaces of a remaining portion of thegermanium material and the dielectric layer. In another embodiment, anadditional slurry composition of the at least one slurry composition mayinclude an abrasive, at least one pH modulator and an oxidizer. In thisembodiment, the at least one pH modulator may include at least one of anacidic pH modulator and a basic pH modulator. In such an example, theadditional slurry composition has an enhanced germanium removal rate,and thus may reduce overburden and planarizes an initial topography ofthe germanium material, prior to the planarization of the germaniummaterial with the slurry composition. This planarization process withthe additional slurry composition may leave a planarized germaniummaterial extending above the topmost surface of the dielectric layer,which can be removed using the slurry composition mentioned above.

In one embodiment, a method for fabricating a semiconductor structure isprovided in which at least one opening is formed within a dielectriclayer disposed above a substrate. A germanium material is epitaxiallygrown within the at least one opening of the dielectric layer, and abovethe topmost surface of the dielectric layer. The germanium material thatis located above the topmost surface of the dielectric layer isplanarized using at least one slurry composition to form coplanarsurfaces of a remaining portion of the germanium material and thedielectric layer. The method, for instance, may further include a slurrycomposition of the at least one slurry composition that polishes thegermanium material selective to the topmost surface of the dielectriclayer, and may include an abrasive, at least one pH modulator, and anoxidizer, with the at least one pH modulator including an acidic pHmodulator, but lacking a basic pH modulator.

In another aspect of the present application, a slurry composition forplanarizing a germanium material is provided that includes a slurrycomposition including an abrasive, at least one pH modulator and anoxidizer. In such implementation, the at least one pH modulator includesat least one of an acidic pH modulator and a basic pH modulator.

In yet another aspect of the present application, a slurry compositionfor planarizing a germanium material is provided that includes a slurrycomposition including an abrasive, at least one pH modulator, and anoxidizer. In such implementation, the at least one pH modulator includesan acidic pH modulator, and lacks a basic pH modulator.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of a structureobtained during semiconductor structure fabrication, and includes adielectric layer disposed over a substrate, in accordance with one ormore aspects of the present application.

FIG. 2A depicts the structure of FIG. 1 after forming one or moreopenings within the dielectric layer, in accordance with one or moreaspects of the present application.

FIG. 2B depicts an alternative embodiment of the structure of FIG. 1after forming one or more openings within the dielectric layer, inaccordance with one or more aspects of the present application.

FIG. 3 depicts the structure of FIG. 2A after epitaxially growing agermanium material in each of the opening(s) which extends above anupper surface of the dielectric layer, in accordance with one or moreaspects of the present application.

FIG. 4 depicts the structure of FIG. 3 with a planarized germaniummaterial having been formed above the upper surface of the dielectriclayer, in accordance with one or more aspects of the presentapplication.

FIG. 5 depicts the structure of FIG. 4 after further planarizing theplanarized germanium material to form coplanar upper surfaces of aremaining portion of the germanium material and the dielectric layer, inaccordance with one or more aspects of the present application.

FIG. 6 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates therate of removal of the germanium material as a function of concentrationof abrasive particles, in accordance with one or more aspects of thepresent application.

FIG. 7 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates thepresence of the oxidizer enhancing the rate of removal of the germaniummaterial, in accordance with one or more aspects of the presentapplication.

FIG. 8 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates therate of removal of dielectric material as a function of concentration ofabrasive particles at various pH values, in accordance with one or moreaspects of the present application.

FIG. 9 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates theeffect of various pH modulators on rate of removal of the germaniummaterial and the dielectric material, in accordance with one or moreaspects of the present application.

FIG. 10 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates therate of removal of the dielectric material and uniformity across thewafer, in accordance with one or more aspects of the presentapplication.

FIG. 11 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates thatpolystyrene sulfonate reduces the rate of removal of the dielectricmaterial, in accordance with one or more aspects of the presentapplication.

FIG. 12 depicts a representative example of the first and the secondslurry compositions utilized in the forming of the coplanar surfaces ofthe germanium material and the dielectric layer, and illustrates thatpoly(acrylic acid) reduces the rate of removal of the dielectricmaterial, in accordance with one or more aspects of the presentapplication.

FIG. 13 depicts an alternative embodiment of the structure of FIG. 5with the germanium material having been partially etched to forming oneor more cavities, in accordance with one or more aspects of the presentapplication.

FIG. 14 depicts the structure of FIG. 13 after epitaxially growing anadditional semiconductor material within the one or more cavities which,for instance, extends above the upper surface of the dielectric layer,in accordance with one or more aspects of the present application.

FIG. 15 depicts the structure of FIG. 14 with a planarized additionalsemiconductor material having been formed above the upper surface of thedielectric layer, in accordance with one or more aspects of the presentapplication.

FIG. 16 depicts a resultant structure of FIG. 15 after planarizing theadditional semiconductor material to form coplanar upper surfaces of theadditional semiconductor material and the dielectric layer, inaccordance with one or more aspects of the present application.

FIG. 17 depicts an alternative embodiment of the structure of FIG. 5,and includes coplanar surfaces of germanium material and a dielectricstack structure disposed over the substrate, in accordance with one ormore aspects of the present application.

FIG. 18 depicts an alternative embodiment of the structure of FIG. 17,and includes coplanar surfaces of additional semiconductor material anda dielectric stack structure disposed over the substrate, in accordancewith one or more aspects of the present application.

FIG. 19 depicts an alternative embodiment of the structure of FIG. 17,and includes coplanar surfaces of the germanium material and adielectric stack structure having one or more sacrificial semiconductorlayer(s) disposed over the substrate, in accordance with one or moreaspects of the present application.

FIG. 20 depicts an alternative embodiment of the structure of FIG. 5,and includes coplanar surfaces of germanium material disposed over aburied template layer, and the dielectric layer, in accordance with oneor more aspects of the present application.

DETAILED DESCRIPTION

Aspects of the present application and certain features, advantages, anddetails thereof, are explained more fully below with reference to thenon-limiting examples illustrated in the accompanying drawings.Descriptions of well-known materials, fabrication tools, processingtechniques, etc., are omitted so as not to unnecessarily obscure thepresent application in details. It should be understood, however, thatthe detailed description and the specific examples, while indicatingembodiments of the present application, are given by way of illustrationonly, and not by way of limitation. Various substitutions,modifications, additions and/or arrangements within the spirit and/orscope of the underlying inventive concepts will be apparent to thoseskilled in the art from this application. Furthermore, reference is madebelow to the drawings, which are not drawn to scale for ease ofunderstanding, wherein the same reference numbers used throughoutdifferent figures designate the same or similar components.

Integration of different semiconductor materials having differentlattice constants is one challenging aspect of forming high performancedevices of future technology nodes. Aspect ratio trapping (ART) is oneway to overcome the lattice mismatch which, for instance, includestrapping threading dislocations of a semiconductor material, such as,for example, a germanium material, along the sidewalls of a dielectriclayer disposed over a semiconductor substrate. In conventional ARTprocessing, the aspect ratio trapping typically includes forming one ormore openings, i.e., trenches, having an aspect ratio (opening depth toopening width) of 1:2 within the dielectric layer. A semiconductormaterial having a different lattice constant than the underlyingsemiconductor substrate is epitaxially grown from an exposed surface ofthe semiconductor substrate within the openings of the dielectric layer,and along the sidewalls of the dielectric layer. This, for instance,results in varying defect density regions of the semiconductor materialbeing located within the openings. For example, a lower region of thesemiconductor material within the opening may have a first defectdensity, and an upper region of the semiconductor material within theopening may have a second defect density that is less than the firstdefect density. The upper region of the semiconductor material extendsabove the dielectric layer. The present application provides an enhancedmethod for CMP processing of the upper region of a germanium materialthat extends above the dielectric layer.

In one embodiment of the present application, a process for facilitatingchemical mechanical planarization of a germanium material is provided.The process includes first providing a dielectric layer having one ormore openings formed therein and located on a substrate. Next, agermanium material is epitaxially grown within the one or more openingsof the dielectric layer disposed over a substrate which, for instance,extends above the dielectric layer. A planarization process inaccordance with the present application is then performed on an upperregion of the germanium material that extends above the at least one ormore openings and on the topmost surface of the dielectric layer. Theplanarization process may include, in one implementation, contacting thegermanium material with a slurry composition that includes an abrasive,a pH modulator having an acidic pH modulator, but lacking a basic pHmodulator, and an oxidizer. The planarization process results in forminga remaining portion of the germanium material that has a topmost surfacethat is coplanar with a topmost surface of the dielectric layer. Theplanarization process of the present application may, in someembodiment, also include planarizing the germanium material with anadditional slurry composition, prior to the planarizing with the slurrycomposition, leaving a planarized germanium material extended above thedielectric layer. In some embodiments, a final surface cleaning may beperformed to remove the remaining first and the second slurry particlesand rinse off other chemicals.

By way of example, FIGS. 1-5 depict one embodiment of a method and oneor more slurry composition(s) to planarize the germanium material thatextend above the upper surface of the dielectric layer, and to form aremaining germanium material in which the topmost surface thereof iscoplanar surface with a topmost surface of the dielectric layer, inaccordance with one or more aspects of the present application.

Referring first to FIG. 1, there is illustrated a structure 200 that canbe employed in accordance with an embodiment of the present application.The structure 200 may include a dielectric layer 204 disposed over, andlocated on, a substrate 202. As depicted, substrate 202 may be (in oneexample) a bulk semiconductor material such as, a bulk silicon wafer,having a first lattice constant. By way of example, the substrate mayinclude a single crystalline silicon material with any suitablecrystallographic orientation. For instance, the crystallographicorientation of the silicon substrate may be {100}, {110} or {111}orientations. In another example, the substrate 202 may be anysilicon-containing substrate including, but not limited to, silicon(Si), polycrystalline Si, amorphous Si or the like. Although notdepicted in the figures, substrate 202 may further include a layeredsemiconductor structure such as, for example, silicon-on-nothing (SON),silicon-on-insulator (SOI), silicon germanium-on-insulator (SiGeOI),germanium-on-insulator (GOI), silicon-on replacement insulator (SRI) orthe like. Substrate 202 may in addition or instead include variousisolation structures or regions, nanowire structures, dopant regionsand/or device features.

The dielectric layer 204, which is disposed on a surface of thesubstrate 202, may be, or include, a dielectric material, such as, forexample, an oxide material, (e.g., silicon dioxide, tetraethylorthosilicate (TEOS), a high density plasma (HDP) oxide, a lowtemperature oxide, a high aspect ratio process (HARP) oxide or thelike), a nitride material (e.g., silicon nitride (SiN)) and/or anoxynitride material (e.g., silicon oxynitride (SiO_(x)N_(y))). Thedielectric layer 204 may be deposited using conventional depositionprocesses such as, for instance, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemicalvapor deposition (LPCVD), or rapid thermal chemical vapor deposition(RTCVD). In one example, the dielectric layer 204 may have thicknesswithin a range from 100 nm to 500 nm.

Other thicknesses that are lesser than, or greater than theaforementioned thickness range may also be employed in the present asthe thickness of the dielectric layer 204.

One or more patterning processes may be performed to form one or moreopenings 206 within the dielectric layer 204, as depicted in FIGS. 2Aand 2B. As illustrated in FIG. 2A, the openings 206 extend down from atopmost surface of the dielectric layer 204 exposing a portion of theunderlying substrate 202. In another embodiment in FIG. 2B, the opening206 may extend below the surface of the substrate 202 creating a cavitywithin the substrate 202. The bottom wall of the cavity may be pointed(as shown) or planar (not shown).

In one embodiment, the patterning process used to define each opening206 may include lithography and etching. Lithography includes forming aphotoresist material (not shown) atop a material or material stack to bepatterned. The photoresist material may include a positive-tonephotoresist composition, a negative-tone photoresist composition or ahybrid-tone photoresist composition. The photoresist material may beformed by a deposition process such as, for example, spin-on coating.After forming the photoresist material, the deposited photoresistmaterial is subjected to a pattern of irradiation. Next, the exposedphotoresist material is developed utilizing a conventional resistdeveloper. This provides a patterned photoresist atop a portion of thematerial or material stack to be patterned. The pattern provided by thepatterned photoresist material is thereafter transferred into theunderlying material layer or material layers utilizing at least onepattern transfer etching process. Typically, the at least one patterntransfer etching process is an anisotropic etch. In one embodiment, adry etching process such as, for example, reactive ion etching can beused. In another embodiment, a chemical etchant can be used. In still afurther embodiment, a combination of dry etching and wet etching can beused. After etching, the patterned photoresist can be removed utilizingany photoresist stripping process such as, for example, ashing.

In another embodiment, the patterning process used to define eachopening 206 may include a sidewall image transfer (SIT) process. In yetanother embodiment, the patterning process used to define each opening206 may include a direct self-assembly (DSA) patterning process.

In an alternative embodiment of the present application, the exemplarysemiconductor structure shown in FIG. 2A and FIG. 2B can be formed byfirst providing a plurality of semiconductor fins (not shown) extendingupwards from a semiconductor substrate utilizing one of the abovementioned patterning processes. Next, a dielectric material thatprovides the dielectric layer 204 is formed between each semiconductorfin and thereafter a planarization process such as, for example,chemical mechanical polishing (CMP) may be employed. Each semiconductorfin is then removed utilizing an etch to form the openings 204. The etchmay include hydrochloric (HCI) gas. A cavity as mentioned above can thenbe formed utilizing an etch such as, for example, a crystallographicetch.

Referring now to FIG. 3, there is illustrated the structure of FIG. 2Aafter epitaxially growing a germanium material 208 in each of theopenings 206. By way of example, the germanium material 208 can beepitaxially grown from an exposed portion of substrate 202 within theopenings 206 using any suitable epitaxial deposition process such as,for instance, atmospheric pressure CVD (APCVD), low- (or reduced-)pressure CVD (LPCVD), ultra-high-vacuum CVD (UHCVD), by molecular beamepitaxy (MBE), metal-organic CVD (MOCVD) or by atomic layer deposition(ALD). In one embodiment, the germanium material 208 may be epitaxiallygrown using a germanium gas source, such as, for instance, germane(GeH₄), digermane (Ge₂H₆), halogermane, dichlorogermane,trichlorogermane, tetrachlorogermane, and combinations thereof. Theepitaxial growth process of the germanium material 208 roceeds upwardsfrom the exposed portion of the substrate 202 and extends above thetopmost surface of the dielectric layer 204. As used herein,“epitaxially growing/growth” refers to the orderly growth of thegermanium material over the exposed portion of the substrate 202, wherethe grown material arranges itself in the same crystal orientation asthe underlying semiconductor material. The germanium material 208 has alattice constant that is greater than the lattice constant of thesubstrate 202. The germanium material 208 has varying defect densitieswithin the openings 206. For instance, and in one embodiment, theepitaxial growth process of the germanium material 208 can result informing a lower region 208 a having a first defect density and an upperregion 208 b having a second defect density, wherein the second defectdensity is less than the first defect density. In some embodiments ofthe present application, threading dislocations within the lower region208 a are trapped along the sidewalls of the dielectric layer 204 in alower region of the openings 206. The epitaxial growth process furtherproceeds to form an overburden portion 208 c that extends above thetopmost surface of the dielectric layer 204. The defect density withinthe overburden portion of the germanium material 208 may be the same as,or less than, the second defect density. The thickness of the overburdenportion 208 c may be sufficient to allow subsequent planarization of thestructure and, in one example, may be within a range from 100 nm to 5μm.

One or more chemical mechanical planarization processes may be employedto planarize the overburden portion 208 c of the germanium material 208.By way of example, the CMP processing may be performed using, forinstance, one or more slurry compositions, each slurry compositionhaving different removal rate selectivity towards the germanium material208 and the dielectric layer 204. As used herein, the first slurrycomposition refers to the additional slurry composition and the secondslurry composition refers to the slurry composition described herein. Insome embodiments, the CMP processing of the present applicationfacilitates selectively planarizing the overburden portion 208 c of thegermanium material 208, without removing the upper region 208 b and thelower region 208 a of the germanium material 208 that is within the oneor more openings 206. Further, the overburden portion 208 c of thegermanium material 208 may have an extremely rough surface,necessitating the first slurry composition to have an enhanced germaniumremoval rate so as to reduce the overburden of the germanium material208 and planarize the initial topography, leaving, at least in part, aplanarized germanium material 208′ extended above the topmost surface ofthe dielectric layer 204, as depicted in FIG. 4. In one embodiment, theenhanced germanium removal rate of the first slurry composition may bewithin a range from 3000 Å/min to 5000 Å/min. In such an embodiment, andsince the first slurry composition only reduces the overburden andplanarizes the initial topography, without exposing the underlyingdielectric layer 204, a removal rate selectivity of the slurrycomposition towards the germanium material 208 and the dielectric layer204 may not be critical. In one example, a first slurry composition maybe employed that is composed of, or includes, an abrasive material, oneor more pH modulators, and an oxidizer. In one embodiment of the presentapplication, the planarized germanium material 208′ may have a thicknessfrom 1000 Å to about 2500 Å.

By way of example, the abrasive particles of the first slurrycomposition may include one or more inorganic particles and/or organicparticles. In one example, each abrasive particle may have an averageparticle diameter of from 5 nm to 500 nm, while in another embodiment,each abrasive particle may have an average particle diameter of from 10nm to 200 nm, the average particle diameter is determined byconventional laser light scattering techniques. An appropriate polishingrate can be achieved, in some embodiments, using abrasive particleshaving an average particle diameter within the ranges mentioned above.The abrasive particles, in one embodiment, may be present in the firstslurry composition in an amount from 0.1 to 30 percent by weight. Inanother embodiment, the abrasive particles may be present in the firstslurry composition in an amount from 0.1 to 10 percent by weight. In oneembodiment, the inorganic particles may include, for instance, silica,alumina, titania, zirconia, ceria, and the like. Examples of silicaparticles that may be employed include, but not limited to, fumedsilica, silica synthesized by a sol-gel method, colloidal silica, or thelike. In one example, the fumed silica may be obtained by reactingsilicon chloride or the like, with oxygen and water in an aqueous phase.In another example, the silica synthesized by a sol-gel method may beobtained by hydrolysis and/or condensation of an alkoxysilicon compoundwhich, for instance, may be used as a raw material. In yet anotherexample, the colloidal silica may be obtained utilizing a conventionalinorganic colloid method. In another embodiment, the organic particlesmay include, but are not limited to, polyvinyl chloride, a styrene(co)polymer, polyacetal, polyester, polyamide, polycarbonate, an olefin(co)polymer, a phenoxy resin, an acrylic (co)polymer, or the like. Inone example, the olefin (co)polymer may include, for instance,polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, andthe like. Examples of the acrylic (co)polymer include polymethylmethacrylate or the like. By way of example, the abrasive particles usedin the first slurry composition can be selected, but not limited to, theexamples of abrasive particles provided in Table 1:

TABLE 1 Particle size (DLS diameter) Silica Association Abrasive *Primary Secondary Number SCM-030B 46.3 nm 74.7 nm 1.61 S32-X02 31.5 nm57.0 nm 1.81 SCM-020B 15.4 nm 42.1 nm 2.73 SCM-070B 46.3 nm 74.7 nm 1.61S32-X04 46.4 nm 54.5 nm 1.17 S32-X05 31.6 nm 37.7 nm 1.19 S32-X08 31.1nm 109.9 nm  3.53 S32-X09 30.5 nm 64.0 nm 2.10 S32-X10 37.4 nm 82.1 nm2.20 S32-X11 90.0 nm 218.0 nm  2.42 S32-X12 13.3 nm 54.5 nm 4.10 S32-X1314.0 nm 17.7 nm 1.26 S32-X16 N/A N/A N/A S32-X17 57.5 nm 63.3 nm 1.10S32-X18 N/A  80 nm N/A S32-X19 N/A N/A N/A S32-X20 N/A N/A N/A S32-X103 12 nm  20 nm 1.66 S32-X104  22 nm  35 nm 1.59 S32-X105  45 nm  80 nm1.78 S32-X106 13.3 nm 54.5 nm 4.10 * All the abrasive particles listedin Table 1 are supplied by JSR Corporation.

Continuing further with FIG. 4, the first slurry composition mayinclude, in one embodiment, one or more acidic pH modulators, and one ormore basic pH modulators, which may modulate the pH of the first slurrycomposition to be in a range from 1 to 12. In some embodiments, the pHrange of the first slurry composition is from 2 to 10. In someembodiments, the acidic pH modulators of the first slurry compositionmay include an inorganic acid, while the basic pH modulators of thefirst slurry composition may include at least one of an organic base andan inorganic base. In one example, the organic base may include, but isnot limited to, tetramethylammonium hydroxide, triethylamine,N-methylethanolamine, methylamine, triethanolamine or the like. Inanother example, the inorganic base may include, but is not limited to,ammonium hydroxide, potassium hydroxide, sodium hydroxide, or the like.In one embodiment of the present application, the inorganic base presentin the first slurry composition is within a range of 0.0001 to 0.1percent by weight. In yet another example, the inorganic acid mayinclude, but is not limited to, nitric acid, sulfuric acid, phosphoricacid or the like. In one embodiment of the present invention, theinorganic acid present in the first slurry composition is within a rangeof 0.0001 to 0.1 percent by weight.

The oxidizer that is present in the first slurry composition may, insome embodiments, facilitate increasing the germanium removal rate ofthe overburden portion 208 c of the germanium material 208 and alsoreduce the surface roughness of the resultant germanium material,subsequent to the planarization processes described herein. As describedfurther below, the oxidizer present in the first and the second slurrycompositions may facilitate achieving an atomically smooth surface ofthe germanium material that is coplanar with a topmost surface of thedielectric layer 204. In one example, the oxidizer includes, but is notlimited to, ceric ammonium nitrate, ferric nitrate, sodium persulfate,potassium persulfate, hydrogen peroxide, potassium permanganate or thelike. By way of an example, the oxidizer present in the first slurrycomposition may be within a range of 0.5 to 200 mL/L. In someembodiment, the range of the oxidizer that is present in the firstslurry composition is from 0.1 to 100 mL/L.

Still further, the first slurry composition may include one or more ofthe following optional components: surfactants, additives, dispersants,polyelectrolytes, soluble polymers and molecules that adsorb onto thesurface of the dielectric layer 204 which, for instance, may improvecolloidal stability and may enhance shelf life of the first slurrycomposition. Additionally, the surfactants may also facilitate removalof the abrasive particles from the substrate surface during the CMPprocessing. In one example, the surfactant is an anionic surfactantwhich may include, for example, a surfactant containing at least onefunctional group selected from a carboxyl group (—COOX), a sulfonic acidgroup (—SO₃X), and a phosphate group (—HPO₄X) (wherein X representshydrogen, ammonium, or a metal). In another example, the anionicsurfactant may include, but is not limited to, aliphatic and aromaticsulfates and sulfonates, and a phosphate salt, or the like. Stillfurther, the anionic surfactants may also include compounds such as, forinstance, potassium dodecylbenzenesulfonate, ammoniumdodecylbenzenesulfonate, sodium alkylnaphthalenesulphonate, alkylsulfosuccinate, potassium alkenylsuccinate, or the like, as well asaliphatic soaps like potassium oleate or the like. The anionicsurfactants may be used either individually or in combination. Inanother aspect, the surfactant is a nonionic surfactant which mayinclude, but is limited to, a polyoxyethylene alkyl ether, an ethyleneoxide-propylene oxide block copolymer, acetylene glycol, an ethyleneoxide addition product of acetylene glycol, an acetylene alcohol, or thelike. In another example, a nonionic polymer compound such as polyvinylalcohol, cyclodextrin, polyvinyl methyl ether, or hydroxyethylcellulosemay be used as the nonionic surfactant. In another embodiment, thesurfactant is a cationic surfactant which may include, but is notlimited to, an aliphatic amine salts, aliphatic ammonium salts, or thelike. In addition, polyelectrolytes, such as, for instance, poly(acrylic acid) and their salts such as sodium, potassium and ammonium,polystyrene sulfonate, carboxymethyl cellulose, polyvinyl pyrrolidoneand polyacrylamides can also be used and added during the polishing tocontrol the selectivity. Other additives such as nitrogen compoundsincluding triazoles, imines, amides and imides can also be used. In aspecific example, the additives may include, but not limited to,benzotriazole, aminotriazole, guanidine hydrochloride, urea derivativesand thioureas.

By way of example, a general formulation of the first slurry compositionhaving a pH within a range of 1 to 12, may include:

-   -   a) Abrasive particle, such as, silica in the range of 0.5 to 30        percent by weight, and more preferably, within a range of 0.1 to        10 percent by weight;    -   b) An acidic pH modulator within the range of about 0.0001 to        0.1 percent by weight;    -   c) A basic pH modulator within the range of 0.0001 to 0.1        percent by weight;    -   d) An oxidizer, such as, 30% solution of hydrogen peroxide        within the range of 0.5 to 200 mL/L, and more preferably, within        the range of 0.1 to 100 mL/L.

The following examples of the first slurry composition are provided tofurther describe the application, and should not be construed as in anyway limiting the scope of the present application. The first slurrycomposition may be prepared by admixing various components, for example,abrasive particle, pH modulators, oxidizers, surfactants, additives,etc.

EXAMPLE 1 A first slurry composition having a pH within a range of 2 to6 was prepared that included:

-   -   a) abrasive particle such as, 5% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator containing an inorganic acid, such as,        for instance, phosphoric acid within a range of 0.0004 to        0.0006% by weight;    -   c) a basic pH modulator containing an inorganic base, such as,        for instance, potassium hydroxide within a range of 0.0005 to        0.002% by weight; and    -   d) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide of 5 mL/L.

EXAMPLE 2

A first slurry Composition having a pH within a range of 2 to 6 wasprepared and included:

-   -   a) abrasive particle such as, 5% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator containing an inorganic acid, such as,        for instance, phosphoric acid within a range of 0.0004 to        0.0006% by weight;    -   c) a basic pH modulator containing an inorganic base, such as,        for instance, potassium hydroxide within a range of 0.0005 to        0.002% by weight; and    -   d) an oxidizer, such as, for instance, 30% solution of hydrogen        of 3 mL/L.

EXAMPLE 3 A first slurry composition having a pH within a range of 2 to6 was prepared and included:

-   -   a) abrasive particle such as, 1% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator containing an inorganic acid, such as,        for instance, phosphoric acid within a range of 0.0004 to        0.0006% by weight;    -   c) a basic pH modulator containing an inorganic base, such as,        for instance, potassium hydroxide within a range of 0.0005 to        0.002% by weight; and    -   d) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide within a range of 0.5 to 5 mL/L.

EXAMPLE 4 A first slurry composition having a pH within a range of 6 to11 was prepared and included:

-   -   a) abrasive particle such as, 5% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator containing an inorganic acid, such as,        for instance, phosphoric acid within a range of 0.0004 to        0.0006% by weight;    -   c) a basic pH modulator containing an inorganic base, such as,        for instance, potassium hydroxide within a range of 0.0005 to        0.002% by weight; and    -   d) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide within a range of 0.5 to 50 mL/L.

One or more chemical planarization steps may be extended using, forinstance, a second slurry composition of the one or more slurrycompositions to polish the remaining planarized germanium material 208′(see FIG. 4) that extends above the topmost surface of the dielectriclayer 204, using (in one embodiment) the topmost surface of dielectriclayer 204, as a polish stop. The result is that topmost surface 212 ofthe remaining portion of the germanium material 208 is coplanar with thetopmost surface 214 of the dielectric layer 204, although heightdifferences may exist locally, as depicted in FIG. 5. By way of example,the second slurry composition may include an abrasive particle, one ormore pH modulators lacking a basic pH modulator, and an oxidizer. Such asecond slurry composition may have a high germanium removal rate and alow dielectric material removal rate which, for instance, facilitatesplanarizing and/or polishing the planarized germanium material 208′ (seeFIG. 4), selective to the dielectric layer 204. In one example, thesecond slurry composition may have a germanium removal rate of 500 Å/minto about 1000 Å/min and a dielectric material removal rate of about 10Å/min to about 50 Å/min. In some embodiments, such a second slurrycomposition may prevent any significant erosion of the dielectric layer204 and may enable complete removal of any residual germanium extendedabove the topmost surface 214 of the dielectric layer 204. The secondslurry composition has a rate of removal of dielectric materials (forinstance, that provide the dielectric layer 204) lower than the rate ofremoval of the germanium material. In one embodiment, the second slurrycomposition may be polish-resistant to at least one dielectric materialthat provides the dielectric layer. As used herein, “polish-resistant”refers to the one or more dielectric materials, such as, oxide and/ornitride materials, that provide the dielectric layer being resistant topolishing and/or planarization processes described herein using thesecond slurry composition. In an embodiment, and when an initialtopography of the overburden germanium material 208 c that extends abovethe dielectric layer 204 is relatively small (for instance, within arange of about 1000 Å-1500 Å), the CMP processing may be accomplishedusing only the second slurry composition, thereby eliminating anadditional CMP processing step using the first slurry composition. Asdepicted, the root mean square (RMS) roughness of the resultantremaining portion of the germanium material 208, having a coplanartopmost surface with the dielectric layer 204, upon CMP processing maybe, in one embodiment, less than 0.5 nm. The remaining portion of thegermanium material 208 has the upper region of the second defect densityand the lower region of the first defect density; the overburden portion208 c has been removed. At this stage of the present application, and insome embodiments, the dielectric layer 204 may be partially recessed toexpose an upper region of the germanium material 208, and asemiconductor device such as, a field effect transistor, can be formedon the exposed surface of the upper region of the germanium layer 208.In other embodiments, a semiconductor device may be formed directly uponthe topmost surface of the remaining portion of the germanium material208 shown in FIG. 5.

Further, in one embodiment, the CMP processing described herein with thefirst slurry composition and the second slurry composition may beaccomplished using the same polishing pad. As one skilled in the artwill understand, the first slurry composition and the second slurrycomposition can be sequentially utilized to form coplanar surfaces ofthe germanium material and the dielectric layer, and can be appliedbetween the polishing pad and the structure. Still further, although notdepicted in the figures, a final surface cleaning process is performedto remove any of the remaining first and the second slurry compositionsand rinse off other chemicals, resulting in the resultant semiconductorstructure.

By way of example, the abrasive particles of the second slurrycomposition may include, one or more inorganic particles and/or organicparticles which may have a particle diameter that is equal to theparticle diameter of the abrasive particles used in the first slurrycomposition, and may be selected from any of the abrasive particlesemployed in the first slurry composition, described above in connectionwith FIG. 4. As described above in connection with the first slurrycomposition, each abrasive particle may have an average particlediameter from 5 nm to 500 nm, or in a range from 10 nm to 200 nm.Further, the abrasive particle, in one embodiment, may be present in thesecond slurry composition in an amount of 0.1 to 30 percent by weight,or in a range of 0.1 to 10 percent by weight. In one embodiment, theabrasive particle of the second slurry composition may be different fromthe abrasive particle of the first slurry composition, while thechemistry of the first slurry composition and the second slurrycomposition may remain the same. In another embodiment, the abrasiveparticle of the second slurry composition may be the same as theabrasive particle of the first slurry composition, but the concentrationof the abrasive particle of the second slurry composition may bedifferent from the concentration of the abrasive particle of the firstslurry composition. In yet another embodiment, the abrasive particle andthe chemistry of the first slurry composition and the second slurrycomposition may be entirely different.

In one implementation, the pH modulator of the second slurry compositionwhich includes an acidic pH modulator, but lacks a basic pH modulator,may modulate the pH of the second slurry composition to be 3 to 11. Inone example, the pH modulator of the second slurry composition may beselected from any of the inorganic acids utilized for the first slurrycomposition, as described above in connection with FIG. 4. For instance,the inorganic acid may include, but is not limited to, nitric acid,sulfuric acid, phosphoric acid or the like. In one embodiment, theinorganic acid present in the second slurry composition is within arange of 0.0001 to 0.1 percent by weight. In another implementation, theoxidizer of the second slurry composition may be selected from any ofthe oxidizer materials of the first slurry composition, described abovein connection with FIG. 4. In one example, the oxidizer present in thesecond slurry composition may be within a range of 0.5 to 200 mL/L, orin a range of 0.1 to 100 mL/L. Additionally, the second slurrycomposition may also include surfactants, additives, dispersants,polyelectrolytes, soluble polymers and molecules that adsorb onto thesurface of the dielectric layers which, for instance, may improvecolloidal stability and may enhance the shelf life of the second slurrycomposition. These materials of the second slurry composition may besimilar or same as the materials utilized for first slurry composition,described above in connection with FIG. 4.

By way of example, a general formulation of the second slurrycomposition having a pH within a range of 3 to 11, may include:

-   -   a) abrasive particle, such as, silica in the range of about 0.5        to about 30 percent by weight, or within a range of 0.1 to 10        percent by weight;    -   b) an acidic pH modulator within the range of 0.0001 to 0.1        percent by weight; and    -   c) an oxidizer, such as, 30% solution of hydrogen peroxide        within the range of 0.5 to 200 mL/L, or within a range of 0.1 to        100 mL/L.

The following examples of the second slurry composition are provided tofurther describe the invention, and should not be construed as in anyway limiting the scope of the invention. The second slurry compositionmay be prepared by admixing various components, for example, abrasiveparticles, pH modulators, oxidizers, surfactants, additives, etc.

EXAMPLE 1 The second slurry composition having a pH within a range of 3to 5 was prepared that included:

-   -   a) abrasive particle such as, 5% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator, such as, for instance, phosphoric        acid within a range of 0.0004 to about 0.0006% by weight; and    -   c) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide of 2 mL/L.

EXAMPLE 2 The second slurry composition having a pH within a range of 3to 5 was prepared and included:

-   -   a) abrasive particle such as, 1% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator, such as, for instance, phosphoric        acid within a range of 0.0004 to 0.0006% by weight; and    -   c) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide of 1 mL/L.

EXAMPLE 3 The second slurry composition having a pH within a range of 3to 5 was prepared and included:

-   -   a) abrasive particle such as, 1% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator, such as, for instance, phosphoric        acid within a range of 0.0004 to 0.0006% by weight; and    -   c) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide within a range of 1 to 5 mL/L    -   d) polyelectrolyte, such as, for instance, polystyrene sulfonate        (having a molecular weight of 10,000 to 400,000) within a range        of 0.01 to 0.1 percent by weight.

EXAMPLE 4 The second slurry composition having a pH within a range of 3to 5 was prepared and included:

-   -   a) abrasive particle such as, 1% by weight of colloidal silica        abrasive dispersed in water;    -   b) an acidic pH modulator, such as, for instance, phosphoric        acid within a range of 0.0004 to 0.0006% by weight;    -   c) an oxidizer, such as, for instance, 30% solution of hydrogen        peroxide within a range of 2.5 to 10 mL/L;    -   d) polyelectrolyte, such as, for instance, poly(acrylic acid)        (having a molecular weight of 400,000) within a range of 0.01 to        0.1 percent by weight.

By way of further clarification, FIGS. 6-12 illustrate representativeexamples of experimental data of the first and the second slurrycompositions described herein to form coplanar surfaces of the germaniummaterial and the dielectric layer, in accordance with one or moreaspects of the present application. The following representativeexamples of the experimental data of the first and the second slurrycompositions should not be construed as in any way limiting the scope ofthe application.

Notably, FIGS. 6-7 depict comparative examples of the rate of removal ofthe germanium material as a function of concentration of abrasiveparticles at various pH values of the slurry compositions describedherein, in accordance with one or more aspects of the presentapplication. As evident from FIGS. 6 and 7, the rate of removal of thegermanium material increases with an increase in concentration of theabrasive particles with the addition of oxidizer, such as, hydrogenperoxide, and that the presence of the oxidizer, such as, for example,hydrogen peroxide in the first and the second slurry compositionprovides an enhanced rate of removal of the germanium material. Further,as depicted in FIG. 8, the rate of removal of the dielectric material,such as, for instance, oxide material, is a function of concentration ofabrasive particles at various pH values with the addition of theoxidizer, for instance, hydrogen peroxide. In one implementation, FIG. 9depicts the effect of various pH modulators on the rates of removal ofthe germanium material and the dielectric material, such as, forinstance, oxide material. For instance, FIG. 9 depicts one example ofthe rates of removal of the germanium material and the oxide materialusing the first and the second slurry compositions having 5% by weightof the abrasive particle (e.g., SCM070B, as supplied by JSR Corporation)at pH value of 10.

By way of further explanation, FIG. 10 illustrates the rate of removalof dielectric material, such as, for instance, oxide material, anduniformity of the dielectric layer across the wafer (for example, havinga diameter of 200 mm) at various applied pressure, and as depicted, therate of removal of the dielectric material is uniformly low resulting incoplanar surfaces of the dielectric layer and the germanium material.Still further, FIGS. 11 and 12 illustrate comparative examples of arelation between the rate of removal of the dielectric material and theconcentration of water soluble polymers, such as, polyelectrolytes(e.g., polystyrene sulfonate (see FIG. 12), and poly(acrylic acid) (seeFIG. 13)), and as evident, illustrates that the polystyrene sulfonateand poly(acrylic acid) reduces the rate of removal of the dielectriclayer having, for instance, nitride material and, for instance, mayserve to act as stop layers.

By way of example, and in one implementation, the RMS roughness of theresultant germanium material 208, upon CMP processing using the firstand the second slurry compositions described herein is less than 0.5 nm,as evident by the examples provided in Table 2. For instance, Table 2illustrates RMS roughness of the resultant germanium material 208 priorto and subsequent to the planarization processes described herein usingthe first and the second slurry compositions (for instance, having anabrasive particle (e.g., SCM-070B, as supplied by JSR Corporation)) atvarious pH values measured in the presence of oxidizers (e.g., hydrogenperoxide) and in the absence of the oxidizers, and that the addition ofoxidizer such as, hydrogen peroxide facilitates achieving atomicallysmooth surface of the germanium material, subsequent to the CMPprocesses described herein.

TABLE 2 Ge RMS roughness (nm) Before After CMP pH CMP No H₂O₂ With H₂O₂Slurry: SCM-070B 1% (W)* 2.3 1.4 2.2 0.3 7 1.4 0.6 0.3 10 1.4 0.6 0.4Slurry: SCM-070B 3% (W)* 2.3 1.4 2.4 0.3 7 1.4 0.8 0.3 10 1.4 0.8 0.3*The abrasive particles listed in Table 2 are supplied by JSRCorporation.

Still further, Tables 3-5 illustrate various examples of the RMSroughness of the germanium material 208 and the dielectric layer 204,prior to and subsequent to the planarization processes described herein,using various pH modulators. For instance, Table 3 illustrates oneexample of the RMS roughness of the germanium material prior to andsubsequent to the planarization processes described herein with variouspH modulators.

TABLE 3 Slurry: SCM-070B 3% (W) pH 10* Ge RMS roughness (nm) pH BeforeAfter CMP adjuster CMP No H₂O₂ With H₂O₂ KOH 1.5 1 0.3 TEA 1.5 0.7 0.5NMEA 1.5 0.4 0.3 *The abrasive particle listed in Table 3 is supplied byJSR Corporation.

Table 4 illustrates another example of a relationship between the rateof removal of the germanium material and the RMS roughness of thegermanium material with the abrasive particle (e.g., 532-X08, assupplied by JSR Corporation), at various pH values in the presence ofoxidizer, such as, for instance, hydrogen peroxide.

TABLE 4 Ge removal rates and RMS surface roughness values for theabrasive S32-X08* Ge RMS roughness removal (nm) rate Before After #Slurry (Å/min) CMP CMP 1 S32-X08 1% (W) pH ~4.3 484 1.4 0.24(unadjusted) + 1 mL/L H₂O₂ 2 S32-X08 2% (W) pH ~4.3 679 1.4 0.22(unadjusted) + 1 mL/L H₂O₂ 3 S32-X08 1% (W) pH 4 598 1.5 0.16(Phosphoric acid) + 1 mL/L H₂O₂ 4 S32-X08 2% (W) pH 4 614 1.4 0.2(Phosphoric acid) + 1 mL/L H₂O₂ 5 S32-X08 1% (W) pH 4 538 1.6 0.17(Acetic acid) + 1 mL/L H₂O₂ 6 S32-X08 2% (W) pH 4 666 1.3 0.2 (Aceticacid) + 1 mL/L H₂O₂ 7 S32-X08 1% (W) pH 6 419 1.5 0.16 (KOH) + 1 mL/LH₂O₂ 8 S32-X08 2% (W) pH 6 575 1.4 0.2 (KOH) + 1 mL/L H₂O₂ *All theabrasive particles listed in Table 4 are supplied by JSR Corporation.

Table 5 illustrates yet another example of a relationship between therate of removal of the germanium material and the dielectric oxidematerial (e.g., oxide material) and RMS roughness value for the abrasiveparticles, such as, S32-X04 and S32-X05 (as supplied by JSRCorporation).

TABLE 5 Ge, oxide removal rates and RMS surface roughness values* RMSroughness Removal rates (nm) (Å/min) Before After Slurry Ge Oxide CMPCMP S32-X04 1% (W) pH 8 + 1 mL/L H₂O₂ 360 6 1.33 0.23 S32-X05 1% (W) pH8 + 1 mL/L H₂O₂ 390 8 1.33 0.18 *All abrasive particles listed in Table5 are supplied by JSR Corporation.

Referring now to FIG. 13, there is illustrated an alternative embodimentof the structure of FIG. 5 with the germanium material 208 having beenpartially etched to form one or more cavities 216 within the dielectriclayer 204, in accordance with one or more aspects of the presentapplication. By way of example, the germanium material may be partiallyetched using any conventional anisotropic dry etching processes, suchas, reactive ion etching, or conventional isotropic etching processes,such as, wet etch processes. In one example, the germanium material 208may be recessed to a depth of 100 nm to 200 nm. As depicted, thegermanium material 208 being etched includes, at least in part, theupper region 208 b having the second defect density and the lower region208 a having the first defect density.

Referring now to FIG. 14, there is illustrated the structure of FIG. 13after epitaxially growing an additional semiconductor material 218within the one or more cavities 216 which extends above the topmostsurface of the dielectric layer 204. The additional semiconductormaterial 218, in one example, may include, or be fabricated of, asemiconductor material, such as, silicon germanium, or a III-V compoundsemiconductor material such as, InSb, GaP, GaN, GaSb, InGaAs, InP, InAs,GaAs, etc., having a lattice constant that is substantially similar orvery close to the lattice constant of the germanium material 208. Theadditional semiconductor material 218 may be formed by an epitaxialgrowth process such as described herein in the forming of the germaniummaterial 208. In one example, the additional semiconductor material 218,such as, silicon germanium material, may be epitaxially grown using asilicon source gas, such as, for instance, silane, disilane, trisilane,tetrasilane, hexachlorodisilane, tetrachlorosilane, dichlorosilane,trichlorosilane, methylsilane, dimethylsilane, ethylsilane,methyldisilane, dimethyldisilane, hexmethyldisilane, and combinationsthereof, and the germanium source gas, such as, for instance, germane,digermane, halogermane, dichlorogermane, trichlorogermane,tetrachlorogermane and combinations thereof. As described above, theadditional semiconductor material 218 may have substantially similarcrystalline characteristics as the germanium material 208 disposedwithin the openings 206. In one embodiment, the thickness of theadditional semiconductor material 218 that extends above the topmostsurface of the dielectric layer 204 may be sufficient to allowsubsequent planarization of the structure. In some embodiments, theadditional semiconductor material 218 may be used to form the channelregions of III-V compound semiconductor material transistor devices suchas, planar CMOS Field Effect Transistor (FETs) or non-planar FinFETdevices to be formed, during subsequent fabrication processing.

One or more chemical mechanical planarization steps may be employed toplanarize the overburden additional semiconductor material 218 thatextends above the topmost surface of the dielectric layer 204, while thegermanium material 208 disposed within the openings 206 remainsunaffected. By way of example, the CMP processing may be accomplishedusing, for instance, the first and the second slurry compositionsdescribed above in connection with FIGS. 4 and 5. For instance, theoverburden additional semiconductor material 218 that extends above thetopmost surface of the dielectric layer 204 may have an extremely roughsurface which, for instance, may be planarized using the first slurrycomposition so as to reduce the overburden and to planarize the initialtopography, leaving a planarized additional semiconductor material 218′extended above the upper surface of the dielectric layer 204, asdepicted in FIG. 15. Further, since the first slurry composition onlyreduces the overburden and planarizes the initial topography, withoutexposing the underlying dielectric layer, a removal rate selectivity ofthe slurry composition towards the additional semiconductor material andthe dielectric layer may not be critical. As described in previousembodiment, the first slurry composition may include an abrasivematerial, one or more pH modulators having an acidic pH modulator and abasic pH modulator, and an oxidizer.

By way of example, the abrasive particles of the first slurrycomposition may include one or more inorganic particles and/or organicparticles which may have a particle diameter that is equal to theparticle diameter of the abrasive particle used in the first slurrycomposition, and may be selected from any of the abrasive particlesemployed in the first slurry composition, described above in connectionwith FIG. 4. In one implementation, the pH modulator of the first slurrycomposition which, for instance, includes an acidic pH modulator and abasic pH modulator, may modulate the pH of the first slurry compositionto be about 3 to about 11. In one example, the pH modulators of thefirst slurry composition may be selected from any of the pH modulatorsutilized for the first slurry composition, as described above inconnection with FIG. 4. In one implementation of the presentapplication, the oxidizer of the first slurry composition may beselected from any of the oxidizer materials of the first slurrycomposition, described above in connection with FIG. 4. Additionally,the first slurry composition may also include surfactants, additives,dispersants, polyelectrolytes, soluble polymers and molecules thatadsorb on to the surface of the dielectric layers which, for instance,improve colloidal stability and enhance the shelf life of the firstslurry composition. These materials of the first slurry composition maybe similar or same as the materials utilized for first slurrycomposition, described above in connection with FIG. 4.

One or more chemical mechanical planarization processing may be extendedusing, for instance, the second slurry composition of the one or moreslurry compositions to polish the remaining planarized additionalsemiconductor material 218′ that extends above the dielectric layer 204,using the topmost surface of the dielectric layer 204, as a polish stop.The result is that topmost surface 220 of the additional semiconductormaterial 218 is substantially coplanar with the topmost surface 222 ofthe dielectric layer 204, as depicted in FIG. 16. As described in theprevious embodiment, the second slurry composition may include, forinstance, an abrasive particle, one or more pH modulators lacking abasic pH modulator, and an oxidizer, along with the surfactants,additives, dispersants, polyelectrolytes described herein in the secondslurry composition utilized in the planarization of the germaniummaterial, and the various materials of the second slurry composition maybe substantially similar or the same materials of the second slurrycomposition described above in connection with FIG. 5. Further, asdescribed above in the previous embodiment, the second slurrycomposition has a high additional semiconductor material removal rateand a low dielectric removal rate which, for instance, facilitatesplanarizing and/or polishing the planarized additional semiconductormaterial, selective to the dielectric layer. This, for instance, mayprevent any significant erosion of the dielectric layer and may enablecomplete removal of any residual additional semiconductor material 218extended above the upper surface 222 of the dielectric layer 204.Further, although not depicted in the figures, a final surface cleaningprocess is performed to remove any of the remaining first and the secondslurry compositions and rinse off other chemicals, resulting in theresultant semiconductor structure.

Referring now to FIG. 17, there is illustrated an alternative embodimentof the structure of FIG. 5, and includes coplanar surfaces of germaniummaterial 208 and a dielectric stack structure 224 disposed over thesubstrate 202. As illustrated in FIG. 17, the dielectric layer 204 may,in an additional or an alternate embodiment, be disposed with one ormore additional dielectric layer(s) 226. In this embodiment, thedielectric layer 204 and the additional dielectric layer(s) 226 togetherdefine one example of a dielectric stack structure 224. By way ofexample, the additional dielectric layer(s) 226 may be, or include, adielectric material, such as, for instance, an oxide material (e.g.,silicon dioxide, tetraethyl orthosilicate (TEOS), high density plasma(HDP) oxide, low temperature oxide, high aspect ratio process (HARP)oxide or the like), a nitride material (e.g., silicon nitride (SiN)) oroxynitride material (e.g., silicon oxynitride (SiO_(x)N_(y))) or thelike, and may be deposited using any of the conventional depositiontechniques described above in connection with the formation of thedielectric layer 204. In some embodiments, the materials of thedielectric layer 204 and the additional dielectric layer 226 may bedifferent. For instance, when the dielectric layer 204 is an oxidematerial, the additional dielectric layer 226 can be a nitride materialor vice versa, which, for instance, results in the additional dielectriclayer 226 serving as a polish stop layer, during the subsequent CMPprocesses. Further, as illustrated in FIG. 18, a portion of thegermanium material 208 may be partially etched to form one or morecavities, as described above in connection with FIG. 13. An additionalsemiconductor material 218, which, in one example, may include or befabricated of a semiconductor material, such as, silicon germanium or aIII-V compound semiconductor material, may be epitaxially grown withinthe cavities, as described above in connection with FIG. 14. Asdescribed above in previous embodiments of the present applications, theadditional semiconductor material 218 extends above the upper surface ofthe dielectric stack structure 224 which, in one embodiment, issubsequently planarized using the first and the second slurrycompositions described in the previous embodiments. The result is thatthe topmost surface 228 of the additional semiconductor material 218 iscoplanar with the topmost surface 230 of the additional dielectric layer226 of the dielectric stack structure 224.

Further, in an additional or an alternative embodiment, the dielectricstack structure 224 may also include one or more sacrificialsemiconductor layer(s) 232, as depicted in FIG. 19. By way of example,the sacrificial semiconductor layer 232 may be, or include a silicongermanium material with multiple layers of varying concentrations. Insuch an embodiment, the additional dielectric layer 226 may serve as aprotective layer so as to protect the various underlying layers of thedielectric stack structure 224. As one skilled in the art willunderstand, the sacrificial semiconductor layer 232 (if present), andthe additional dielectric layer 226 over the sacrificial semiconductorlayer 232 may be formed over the dielectric layer 204, resulting in thedielectric stack structure 224. The dielectric stack structure 224 maysubsequently be patterned and etched to form one or more opening(s) (notshown) using any of the conventional lithographic patterning processes,as described above in connection with the formation of opening(s) 206 inFIG. 2A or FIG. 2B. The germanium material 208 may be subsequentlydeposited within the openings, as described in previous embodiments, andplanarized using the first and/or the second slurry compositions asdescribed in previous embodiments. As depicted further in FIG. 19, thegermanium material 208 may be planarized, using the first and the secondslurry compositions described in the previous embodiments, resulting inthe upper surface 228 of the germanium material 208 being substantiallycoplanar the upper surface 230 of the additional dielectric layer 226.Note that, as described in the previous embodiments, the one or moreslurry compositions, in particular, the second slurry compositiondescribed herein has a rate of removal of the additional dielectricmaterial (e.g., oxide and/or nitride materials) that is lower than therate of removal of the germanium material. In one embodiment, the secondslurry composition may be polish-resistant to any of the materials ofthe additional dielectric layer 226.

Referring now to FIG. 20, there is illustrated an alternative embodimentof the structure of FIG. 5, and includes coplanar surfaces of germaniummaterial 208 disposed over a buried template layer 234, and thedielectric layer 204, in accordance with one or more aspects of thepresent application. By way of example, the buried template layer 234,which, for instance, may be, or include, any suitable III-V templatelayer, may be epitaxially grown within the openings 206 of thedielectric layer 204, prior to the epitaxial growth of the germaniumlayer 208. In such an embodiment, the buried template layer 234 mayserve to act as a buffer layer and enable a defect-free epitaxial growthof the germanium material over the exposed portions of the substrate202. As described above in previous embodiments, the germanium material208 extends above the upper surface of the dielectric layer 204 which,for instance, is subsequently planarized using the first and the secondslurry compositions described in the previous embodiments. The result isthat the topmost surface 212 of the germanium material 208 beingcoplanar with the topmost surface 214 of the dielectric layer 204.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the application.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has” and “having”), “include” (and any formof include, such as “includes” and “including’), and “contain” (and anyform of contain, such as “contains” and “containing”) are open-endedlinking verbs. As a result, a method or device that “comprises”, “has”,“includes” or “contains” one or more steps or elements possesses thoseone or more steps or elements, but is not limited to possessing onlythose one or more steps or elements. Likewise, a step of method or anelement of a device that “comprises”, “has”, “includes” or “contains”one or more features possesses those one or more features, but is notlimited to possessing only those one or more features. Furthermore, adevice or structure that is configured in a certain way is configured inat least that way, but may also be configured in ways that are notlisted.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below, if any, areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed. The description of the present application has been presentedfor purposes of illustration and description, but is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of theapplication. The embodiment was chosen and described in order to bestexplain the principles of one or more aspects of the invention and thepractical application, and to enable others of ordinary skill in the artto understand one or more aspects of the present invention for variousembodiments with various modifications as are suited to the particularuse contemplated.

What is claimed is:
 1. A method for fabricating a semiconductorstructure, the method comprising: forming a dielectric layer containingat least one opening, the dielectric layer is located on a substrate;epitaxially growing a germanium material within the at least oneopening, the germanium material extending above a topmost surface of thedielectric layer; and planarizing the germanium material using at leastone slurry composition to form coplanar surfaces of the germaniummaterial and the dielectric layer, wherein a slurry composition of theat least one slurry composition polishes the germanium materialselective to the topmost surface of the dielectric layer, and comprisesan abrasive, at least one pH modulator, and an oxidizer, the at leastone pH modulator comprising an acidic pH modulator, and lacking a basicpH modulator.
 2. The method of claim 1, wherein the slurry compositionof the at least one slurry composition has a rate of removal of thegermanium material greater than a rate of removal of the dielectricmaterial.
 3. The method of claim 1, wherein the slurry composition ispolish-resistant to at least one dielectric material that provides thedielectric layer.
 4. The method of claim 1, wherein the at least oneslurry composition comprises an additional slurry composition, and theplanarizing comprises planarizing the germanium material using theadditional slurry composition, prior to the planarization with theslurry composition.
 5. The method of claim 4, wherein the additionalslurry composition of the at least one slurry composition planarizes aninitial topography of the germanium material.
 6. The method of claim 4,wherein the additional slurry composition of the at least one slurrycomposition has an enhanced rate of removal of the germanium materialrelative to the slurry composition of the at least one slurrycomposition.
 7. The method of claim 4, wherein the additional slurrycomposition of the at least one slurry composition has a chemicalcomposition that is different from a chemical composition of the slurrycomposition of the at least one slurry composition.
 8. The method ofclaim 4, wherein the additional slurry composition of the at least oneslurry composition comprises an abrasive, at least one pH modulator andan oxidizer, wherein the at least one pH modulator comprises at leastone of an acidic pH modulator and a basic pH modulator.
 9. The method ofclaim 4, wherein the germanium material has a first lattice constant,and the substrate comprises a semiconductor material having a secondlattice constant, the first lattice constant of the germanium materialbeing greater than the second lattice constant of the semiconductorsubstrate.
 10. The method of claim 4, wherein the germanium materialincludes a lower region having a first defect density within a lowerregion of the at least one opening, an upper region having a seconddefect density that is less than the first defect density located in anupper region of the at least one opening, and an overburden portion thathas a defect density that is equal to, or less than, the second defectdensity and located above the topmost surface of the dielectric layer,and wherein the additional composition removes the overburden of thegermanium material.
 11. The method of claim 1, further comprising aburied template layer disposed within the at least one opening of thedielectric layer, the semiconductor material being epitaxially grownover the buried dielectric layer, wherein the buried template layerfacilitates defect-free epitaxial growth process of the semiconductormaterial.
 12. The method of claim 1, further comprising etching thegermanium material, subsequent to forming coplanar surfaces of thegermanium material and the dielectric layer, to form a cavity within theat least one opening, and the epitaxially growing comprising epitaxiallygrowing an additional semiconductor material within the cavity, theadditional semiconductor material extending above the dielectric layer.13. The method of claim 12, wherein the substrate comprises a firstsemiconductor material and the additional semiconductor materialcomprises a second semiconductor material, the first semiconductormaterial and the second semiconductor material being differentsemiconductor materials, and the additional semiconductor materialcomprising a Group III-V semiconductor material.
 14. The method of claim12, wherein the planarizing of the additional semiconductor materialusing the at least one slurry composition forms the coplanar surfaces ofthe additional semiconductor material and the dielectric layer.
 15. Themethod of claim 1, further comprising a dielectric stack structuredisposed over the substrate, the dielectric stack structure comprisingthe dielectric layer, and at least one layer disposed over thedielectric layer, wherein the at least one layer comprises at least oneof an additional dielectric layer and a sacrificial semiconductormaterial.
 16. A slurry composition for planarizing a germanium material,the slurry composition comprising: an abrasive, at least one pHmodulator and an oxidizer, wherein the at least one pH modulatorcomprises at least one of an acidic pH modulator and a basic pHmodulator.
 17. A slurry composition for planarizing a germaniummaterial, the slurry composition comprising: an abrasive, at least onepH modulator, and an oxidizer, wherein the at least one pH modulatorcomprises an acidic pH modulator, and lacks a basic pH modulator. 18.The slurry composition of claim 17, wherein the slurry composition ispolish-resistant to at least one dielectric material that provides adielectric layer.
 19. The slurry composition of claim 17, wherein theslurry composition has a rate of removal of the germanium materialgreater than a rate of removal of the dielectric material.
 20. Theslurry composition of the claim 17, wherein the acidic pH modulator ofthe slurry composition includes an inorganic acid in an amount from0.0001% to 0.1% by weight based on a total weight of the slurrycomposition.